1. Field of the Invention
This invention relates generally to apparatus for treating crankcase vapor emissions of internal combustion engines, particularly automotive engines, to improve the efficiency of such engines and to reduce the concentration of unburned hydrocarbons and carbon in the "blow-by" gases from such engines as a pollution control measure.
2. Description of the Prior Art
Automotive internal combustion engines have been identified as the major contributor to air pollution. During the operation of internal combustion engines a small portion of the air-fuel mixture fed to the cylinders of these engines passes by the pistons and piston rings into the crankcase before combustion occurs. Also, after combustion of the air-fuel mixture in the cylinders of internal combustion engines, combustion exhaust gases are forced past the piston rings into the crankcase immediately after combustion takes place. The unburned air-fuel vapor mixture and combustion exhaust gases (including water vapor, oil vapor, carbon dioxide and carbon monoxide) entering the crankcase are collectively called "blow-by" gasses. Blow-by gases are a problem since, if they are permitted to remain in the crankcase, they form various deposits, acids and sludges which are harmful to engine life and performance.
In the past blow-by gases were vented to the atmosphere. However, in recent years concern with air pollution has created a need for preventing crankcase vapors from discharging into the atmosphere. Thus, positive crankcase ventilation (PCV) systems have been developed which recycle engine blow-by gases back into the air-fuel introduction system of the engine and thereafter into the combustion chambers where hydrocarbons in such gases can be combusted.
In order to maintain combustion efficiency a flow control valve has been commonly interposed in the conduit conducting the blow-by gases and vapors from the crankcase to the intake mainfield of the engine. This flow control valve, identified conventionally as a PCV valve, is normally modulated either in relation to the pressure or vacuum in the crankcase or by the amount of vacuum in the intake manifold. With the PCV valve working properly increased milage is experienced because of the return of unburned hydrocarbons to the combustion chambers of the engine.
The PCV valve, which meters the flow of the crankcase emissions, frequently sticks or becomes clogged in one position causing excessive air flow and unbalance in the engine's air-fuel ratio causing rough idling or stalling. If the PCV valve sticks in the other position there is reduced air flow and the blow-by gases are not carried off with the result that the crankcase becomes contaminated with sludge, acid and other harmful products which cause engine corrosion, poor lubrication and (eventually) serious engine damage if the PCV valve is not cleaned or replaced.
Further, the PCV valve is frequently clogged because the crankcase emissions not only are comprised of air and blow-by gases and vapors which pass through such valve, but also contain water and water vapor, oil vapor, resins, varnishes and acids, as well as products of a carbonaceous and calcareous nature. Also, solids such as soot, dust and various oxidation products are present and further tend to interfere with the operation of the PCV valve.
In order to maintain the PCV valve and the engine in good operating condition, it is desirable to separate out and collect the harmful heavy components found in crankcase emissions while permitting the light unburned gaseous hydrocarbons and air to pass through the PCV valve and thence to the intake manifold of the engine.
The patent literature suggests several types of devices which remove at least some of the harmful components found in crankcase emissions and which allow the lighter hydrocarbon components of such emissions to be returned to the engine for combustion therein. U.S. Pat. No. 3,463,132 to W. S. Krieck, U.S. Pat. No. 3,779,221 to J. J. Gartner, and U.S. Pat. No. 4,089,309 to E. M. Bush all disclose and claim apparatus for improving the efficiency of an internal combustion engine including a filter unit connected between the crankcase and the inlet manifold of the engine. The devices of these patents are relatively complex and costly to produce and maintain and there remains a need for simplified, but unique, apparatus for separating and collecting the heavy deleterious components of crankcase emissions to improve engine efficiency and reduce air pollution.